Improvement in roof-trusses



UNITED STATES NIEATENT Grrrcn.

PETER L. VVEIMER, OF LEBANON, PENNSYLVANIA.

IMPRovx-:MENT IN aooareusses.

Speciication forming part of Letters Patent No. 146,114, dated December 30,1873 application led November 29, 1873.

f1 o all 107mm it may concern:

Be it known that I, PETER L. WEIMER, of Lebanon7 in the county of Lebanon and State of Pennsylvania, have invented a new and useful Improvement in Truss-Frames for Roofs; and I do hereby declare that the'following is a full, clear, and exact description of the same, reference being had to the accompanying drawings forming part of this specification, in which- Figure l is a side elevation of my improved truss-frame, and Fig. 2 a similar view of the truss-frame modified.

In the construction of trussed roofs it is essential that the principal rafters receive support, at intervals, from compression-picces, which rest upon the tie-beam and have their thrust conveyed, by means of bolts, to the junction of the principal rafters. The nature of my invention consists in a truss-frame for a roof which has only two points in the tie beam, which receive the thrust of the compression pieces, while each of the principal rafters of the truss have, between those ends which rest upon the tie-beam and those which adjoin, two, three, or more points of support from the compression-pieces, and the thrust of these compression-pieces is conveyed to the junction of the principal rafters by only two bolts.

In Fig. l, A represents the tie-beam; B B, the principal rafters; C, the wedge block or key at the junction of the rafters; D D', the two bolts which extend upfrom the tie-beam and cross one another just at the base of the wedge-block or key piece C. E E are upright supporting and compression pieces between the principal rafters and the tie-beam 5 and F F are oblique auxiliary supporting and compression pieces, also between the rafters and the tie-beam. The foot of the piece E rests upon the tie-beam just at the point where the bolt D passes up through this beam, and the foot of the piece F rests upon said beam and against the foot of the piece E. The pieces E F are arranged in the same manner upon the beam, and in the same relation to the principal rafters and the bolt D', as just described, except that the oblique piece F is inclined in a converse direction to the oblique piece F.

From the drawing, Fig. -1, it will be seen there are four compression-pieces, E E' F F', resting on the tie-beam at the twopoints 1 1, and against the principal rafters at the four points 2 2 2 2. In Fig. 2 the tie-beam, rafters,

and bolts are the same as in Fig. 1, but the compression-pieces E E are set oblique instead of upright, the inclination of E being the converse of E', and, instead of using only two auxiliary supporting and compression pieces, four auxiliary supporting and compression pieces, F F F' F', are employed, and these pieces extend down from the principal rafters and bear against the oblique main supporting and compression pieces E El at apoint about i and between every pair of auxiliary compres` sion-pieces auxiliary bolts extending from the head of one piece to the foot of another piece,` had to be employed. This plan necessitates.. the use of very heavy bolts, and the roof is not as strong as my roof.

I am also aware that a truss with central bolt, and with inclined compression-pieces extending down from the rafters to the foot of this bolt, and then two auxiliary vertical side bolts and similar auxiliary compression-pieces extending down from the head of said auxili-` ary bolts to the foot of the main central bolt, has been devised. But in that plan of construction the wlrole weight is transmitted to one central point on the tie-beam, and, consequently, while great strength and weight in the central bolt are required, the roof is not as strong as mine, for the reason that the larger bolt and auxiliary bolts necessitate the weakening of the beam at the `points where they pass through it.

I am also aware that, in trusses where the tensile parts are made of metal, compress1on-V pieces and tension-rods have been combined with the main rafters and tie-beam in such a t manner that some of the thrust pieces are con nected directly to the rafters and to the tiebeam, and the others to the main rods directly, so as to be sustained thereby. This roof subjects the builder, in a given length of span, to the expense of nine separate rods and four knuckles, while inine only requires five rods and two knuckles. To secure the benefit of three thrustsupports, in a similar roof, on eaeh rafter, as in my modified plan, it would be necessary, under the known construction of the most approved truss, to use thirteen tension-rods and six knuckle-joints, while in my construction, Fig. 2, only two main bolts, or five rods and two knuckles, are necessary.

I also am aware that a truss with a singleY support for each rafter, combined with two diagonally-crossed bolts, has been-proposed; but this plan is not useful for any length of span, and when the span is increased, and it is desired to get the requisite support for the rafters, it is usual to adopt one or the other of I Weight upon the truss is conveyed and supported at two 'points on the tie-beam, substantially as described.

PETER L. VVEIMER. W'itnesses M. R. WEIMER, A. WEIMER. 

